GS6151 Datasheet, PDF (41/77 Pages) Semtech Corporation – Multi-Rate 6G UHD-SDI

Figure 4-22: Example Eye Monitor Bitmap
With the eye monitor enabled by setting the HORIZONTAL_EYE_MON_ENABLE bit an
eye scan is started by writing a 1 to the AUTO_SCAN_START bit of the
EYE_MON_SCAN_START register. The eye-scan state machine then scans the eye and
writes a 0 to the AUTO_SCAN_START bit when it completes. The values in the above
registers are then valid if lock was not lost at any point during the eye scan. It is therefore
recommended that the LOCK_LOST_STICKY bit of the STICKY_STATUS register is
cleared before running the eye scan and checking its value after the eye scan is
complete.
After a successful automatic eye scan, the EYE_WIDTH bits hold a value corresponding
to the number of phases that had errors that did not exceed a predefined threshold. This
error threshold is defined as the number of errors that must be observed before the
phase is deemed to be not error-free and is set in the ERROR_THRESHOLD bits of the
EYE_MON_CONTROL_REG_4 register. By default the error threshold is set to 3.
A typical relationship between the EYE_WIDTH result and the input jitter amplitude is
given in Figure 4-22.
GS6151
Final Data Sheet
PDS-060389
Rev.4
August 2015
www.semtech.com
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